Its touched on a little, but I don't think the features like comments and so on were the trigger. Most of the sites that offered video back then all had some funky player that required downloading some codec that only worked half the time. Youtube just worked everywhere thanks to Flash. If they had gone with a less ubiquitous format, even if they had all the other features they mention, I don't think it would be what it is today.
The biggest take away for me from this was just how recent this whole video UGC thing is. Its hard to imagine a world without YouTube now.
I think that a huge portion of the success of YouTube is not just the not having a codec issue, but the immediate start of the videos. Sites like iFilm in particular, were around for a number of years before YouTube, but before Flash 7, they all had buffering delays. If you remember back with RealAudio 1.0, there was no buffering, and so every time a packet dropped, the sound would cut out. The response to this was to buffer up for 15-20 seconds before starting playback. This worked ok if you knew you wanted to listen or watch something, and it was long. What Adobe seemed to realize was that you're better off starting immediately and building up your buffer as you go along. You may get some stuttering at the beginning, but it's a small price to pay for starting immediately.
Starting the video immediately made YouTube addictive, literally. Shortening the time between following a link and seeing something funny makes the user want to click again.
In the video he touches on several points crucial for a successful startup including believing in your idea when no one does. Paradoxically, unlike many startup founders (Yahoo, Google, Microsoft) who left schools to focus on their business, he chose the opposite course and left business to join graduate school at Stanford just when YouTube was taking off. If he departed because he never expected YouTube to be a runaway hit (a belief augmented by initial hiccups YouTube met with) or if it was genuinely the allure of academia that he couldn’t resist is anybody’s guess. Does he regret having left YouTube in haste?
As I expected, it didn't mention the fortitude they had to fend of lawsuits over the copyrighted clips that were prevalent early on. That alone drove a large part of the growth.
On the flip side, a more subtle point that held them back a bit was an overwhelming community sense of _not_ linking to youtube videos in many discussion forums, because it seemed like unnecessary advertising for their brand. That sentiment was short lived due to the soon to be overwhelming benefit of those aforementioned copyrighted hosted clips.
The biggest take away for me from this was just how recent this whole video UGC thing is. Its hard to imagine a world without YouTube now.